Salt cell not working?

[slepax]

Hello all,

Recently we have had issues with the SWG unit showing low salt warnings. Testing for salt levels we see good amount of salt (6800 ppm). I would immediately suspect the salt cell due to its age (6.5 years old), but ...

• The issue is not consistent, sometimes the low salt warning message appears and sometimes it doesn't
• When the low salt warning shows, the SWG also shows that chlorine generated is low (e.g. 1 out of 8 bars) and no "white mist" is present in the cell
• When the low salt warning shows, running the pump on high (2200 rpm) for a few seconds fixes the issue, after that pump can go back to medium/low (1200 rpm) and chlorine is produced at appropriate levels (also showing "white mist") with no low salt warning

Due to the age of the cell any shop would immediately suggest replacing it, however I really want to understand the problem before doing that.

As a side note, and something that I am really keen to understand for my own learning - what makes a salt cell go bad? I understand there is a coating on the plates that makes the conversion but is there a way to see if the plates are "dead"? Surely age is just an indication, what is the real cause for a salt cell to stop working?

The photo below shows the coating fading out on one of the plates, does that mean anything?

Many thanks!

 

[Texas Splash]

I'm not familiar with the Viron V18 SWG, but a salt level of 6,800 seems incredibly high. I'm curious, your season is just beginning I believe. How's your water temp? Any chance the water is still cold throwing-off the SWG?

 

[slepax]

During winter the SWG was set to low production so I did not notice the issue. I have only started noticing this issue a few weeks ago with water temp around 22 deg, weather has been pretty hot over the last couple of weeks and the temp now is 28 deg.

You are right 6800 is very high, we've had to top up water a couple of times recently so I will get another check done today and see where the level is at.

 

[Costas > DownUnder]

- what makes a salt cell go bad?

There are a couple of reasons why cells can fail:

- As you mention - Eventual plating loss on the plates due to current flow between the plates.​

- Physical plate wear due to mechanical erosion from fast flowing water.​

- Some cells can suffer mechanical wear/erosion to the actual connections to the plates and not the plate itself. When the connection fails no current flows.​

- PH level of your water way too high/low for long periods of time.​

- Cleaning the cells too often and/or too aggressively which damages the plating prematurely.​

​

To obtain maximum life for your cell:

- Keep CSI in check (slightly negative) to prevent calcium buildup on the plates thereby reducing/eliminating the need to clean the cell​

- Keep runtime hours to a minimum - Achieved by selecting an oversized cell for your given pool volume. Cell can then produce a larger amount of chlorine gas per hr which translates to less overall runtime for the cell.​

- Keeping drive level to the cell at lower levels - Some chlorinators can adjust the drive level to the cell - In conjunction with my second point above, An oversized cell can be driven at lower drive levels (in conjunction with shorter runtimes) and still produce substantial chlorine amounts. By running reduced current flow across the plates it can aid in reduced plate wear & tear.​

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Best way to determine when a cell goes bad is to measure the voltage and current flow through of a brand new cell at a given drive level with a known salinity level and record this value.​

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When the cell starts to deteriorate, the current flow will reduce over time for the same drive level given the same level of water salinity. Once it starts to drop off too far then it is time to replace.​

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BTW - What are you using to measure your salt levels?​

 

[slepax]

BTW - What are you using to measure your salt levels?

One of the shops around here. The Taylor kit I have doesn't test salt levels.

The previous test was on 26/Oct showing 6848ppm and today (16/Nov) showing 10,000ppm, that's without adding any salt and adding more water! Everything is out of whack in this test, this shop uses something called Filtrite Flow water analysis. I'll take another sample to a different shop tomorrow and see what comes out.

 

[Costas > DownUnder]

One of the shops around here.

Everything is out of whack in this test,

Welcome to the world of pool shop testing where you will probably have more luck in selecting winning numbers in the Lotto draw.

Since you are in Aus, grab a test kit off Brett over at Clear Choice Labs – Simple. Accurate. Fast. - You will never go back to store testing again.